In July for many years, stations in Europe have been able to work stations on 6m (VHF) in Japan. A look at the map will show this is a very long way.
The most credible explanation is this is caused by ionisation in the mesosphere linked to the formation of noctilucent clouds that form at this time. From research, this path could work at even higher frequencies, possibly microwaves! What is needed is for keen people at each end to try.
This is definitely a case when research by radio amateurs could advance radio science. There is much to be gained from this research. I think noctilucent clouds are becoming more common as a result of climate change, but don't quote me on this. Certainly Far East stations have been spotted here on just a vertical omni on 6m FT8 for several years in July.
Now is the time to arrange some skeds on 2m, 70cm or 23cm. Records could tumble.
See https://sites.google.com/view/g3xbm4/home/vhfuhfmicrowaves/super-dx .
These are just high altitude Ice clouds. Why would they have radio-reflecting or refracting properties? Isn't it more likely to be some kind of solar ionizing (like all the other reflective layers?) G6AIG by the way.. good to see you are still blogging..
ReplyDeleteIf you read the original article this is indeed a puzzle.
ReplyDelete"VHF radars see very strong echoes from these clouds"
I have no idea of the why,but,from personal experience 6m super DX occurs every July, just like clockwork. I have lost count of how many Japanese stations I have spotted on 6m in July!